how to update an array using rapidjson?

Question

i doing some stuff with rapidjson and i want to add values to an array i just created like that

#include <iostream>
#include "rapidjson/document.h"
using namespace std ;

int main() {


    char json[1024];
    rapidjson::Document document ;
    document.Parse<0>(json);
    if (!document.IsObject()) {
            document.SetObject();
    }
    assert(document.IsObject());
    rapidjson::Document::AllocatorType& allocator = document.GetAllocator();
    // adding member (int)
    document.AddMember("mohammed",25,allocator);
    assert(document.HasMember("mohammed"));
    cout << document["mohammed"].GetInt() << endl ;

    // adding member (array)
    rapidjson::Value array(rapidjson::kArrayType);
    array.PushBack(5,allocator);
    array.PushBack(6,allocator);
    cout << array[0u].GetInt() << endl ;
    cout << array[1].GetInt() << endl ;
    document.AddMember("array",array,allocator);
    assert(document.HasMember("array"));
    assert(document["array"].IsArray());
    // here the following line give me an error 
    array.PushBack(7,allocator);




}

the error is

json: rapidjson/document.h:397: rapidjson::GenericValue<Encoding, Allocator>& rapidjson::GenericValue<Encoding, Allocator>::PushBack(rapidjson::GenericValue<Encoding, Allocator>&, Allocator&) [with Encoding = rapidjson::UTF8<>; Allocator = rapidjson::MemoryPoolAllocator<>]: Assertion `IsArray()' failed.

Aborted (core dumped)

what is the problem can someone explain? what is happening i am kinda new to this,thank you.

Answer 1

When array.PushBack(...) is being executed, array has already been moved into document, and becomes a null value type (array.IsNull() == true). So you cannot PushBack to a null value.

document["array"].PushBack(7,allocator) will work.